scholarly journals PplD is a de-N-acetylase of the cell wall linkage unit of streptococcal rhamnopolysaccharides

2021 ◽  
Author(s):  
Jeffrey S. Rush ◽  
Prakash Parajuli ◽  
Alessandro Ruda ◽  
Jian Li ◽  
Amol A. Pohane ◽  
...  
Keyword(s):  
Cell Wall ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Antimicrobial Proteins ◽  
Promising Target ◽  
Highly Sensitive ◽  
Streptococcal Species ◽  
Group A ◽  
Base Mechanism ◽  
Nmr Methods

The cell wall of the human bacterial pathogen Group A Streptococcus (GAS) consists of peptidoglycan decorated with the Lancefield group A carbohydrate (GAC). GAC is a promising target for the development of GAS vaccines. In this study, employing chemical, compositional, and NMR methods, we show that GAC is attached to peptidoglycan via glucosamine 1-phosphate. This structural feature makes the GAC-peptidoglycan linkage highly sensitive to cleavage by nitrous acid and resistant to mild acid conditions. Using this characteristic of the GAS cell wall, we identify PplD as a protein required for deacetylation of linkage N-acetylglucosamine (GlcNAc). X-ray structural analysis indicates that PplD performs catalysis via a modified acid/base mechanism. Genetic surveys in silico together with functional analysis indicate that PplD homologs deacetylate the polysaccharide linkage in many streptococcal species. We further demonstrate that introduction of positive charges to the cell wall by GlcNAc deacetylation protects GAS against host cationic antimicrobial proteins.

A highly sensitive immuno-PCR assay for detecting Group A Streptococcus

2003 ◽  
Vol 279 (1-2) ◽  
pp. 101-110 ◽  
Author(s):  
Huining Liang ◽  
Susan E. Cordova ◽  
Thomas L. Kieft ◽  
Snezna Rogelj
Keyword(s):  
Group A Streptococcus ◽  
Pcr Assay ◽  
Highly Sensitive ◽  
Group A

Electron microscopy of the replicative events of A25 bacteriophages in group A streptococci

1972 ◽  
Vol 18 (1) ◽  
pp. 93-96 ◽  
Author(s):  
S. E. Read ◽  
R. W. Reed
Keyword(s):  
Electron Microscopy ◽  
Cell Wall ◽  
Electron Microscope ◽  
Nucleic Acid ◽  
Group A Streptococcus ◽  
Group A Streptococci ◽  
Virulent Phage ◽  
Acid Pool ◽  
Group A ◽  
A Cell

The replicative events of a virulent phage (A25) infection of a group A Streptococcus (T253) were studied using the electron microscope. The first intracellular evidence of phage replication in a cell occurred 30 min after infection with arrest of cell division and increase in the nucleic acid pool. Phage heads were evident in the nucleic acid pool of the cells 45 min after infection. Release of phages occurred by splitting of the cell wall along discrete lines. This appeared to be at sites of active wall synthesis, i.e., near the region of septum formation. Many phage components were released but relatively few complete phages indicating a relatively inefficient replicative system.

scholarly journals Biochemical and biological activity of arginine deiminase from Streptococcus pyogenes M22

2016 ◽  
Vol 94 (2) ◽  
pp. 129-137 ◽  
Author(s):  
Eleonora A. Starikova ◽  
Alexey V. Sokolov ◽  
Anna Yu. Vlasenko ◽  
Larisa A. Burova ◽  
Irina S. Freidlin ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Endothelial Cells ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Arginine Deiminase ◽  
Dependent Manner ◽  
Group A ◽  
Micro Organisms ◽  
Dose Dependent

Streptococcus pyogenes (group A Streptococcus; GAS) is an important gram-positive extracellular bacterial pathogen responsible for a number of suppurative infections. This micro-organism has developed complex virulence mechanisms to avoid the host’s defenses. We have previously reported that SDSC from GAS type M22 causes endothelial-cell dysfunction, and inhibits cell adhesion, migration, metabolism, and proliferation in a dose-dependent manner, without affecting cell viability. This work aimed to isolate and characterize a component from GAS type M22 supernatant that suppresses the proliferation of endothelial cells (EA.hy926). In the process of isolating a protein possessing antiproliferative activity we identified arginine deiminase (AD). Further study showed that this enzyme is most active at pH 6.8. Calculating Km and Vmax gave the values of 0.67 mmol·L–1 and 42 s−1, respectively. A distinctive feature of AD purified from GAS type M22 is that its optimum activity and the maximal rate of the catalytic process is close to neutral pH by comparison with enzymes from other micro-organisms. AD from GAS type M22 suppressed the proliferative activity of endothelial cells in a dose-dependent mode. At the same time, in the presence of AD, the proportion of cells in G0/G1 phase increased. When l-Arg was added at increasing concentrations to the culture medium containing AD (3 μg·mL–1), the enzyme’s capacity to inhibit cell proliferation became partially depressed. The proportion of cells in phases S/G2 increased concomitantly, although the cells did not fully recover their proliferation activity. This suggests that AD from GAS type M22 has potential for the suppression of excessive cell proliferation.

scholarly journals A Novel Sortase, SrtC2, from Streptococcus pyogenes Anchors a Surface Protein Containing a QVPTGV Motif to the Cell Wall

2004 ◽  
Vol 186 (17) ◽  
pp. 5865-5875 ◽  
Author(s):  
Timothy C. Barnett ◽  
Aman R. Patel ◽  
June R. Scott
Keyword(s):  
Cell Wall ◽  
Streptococcus Pyogenes ◽  
Group A Streptococcus ◽  
Surface Protein ◽  
Surface Proteins ◽  
Human Pathogen ◽  
Hydrophobic Region ◽  
C Terminus ◽  
Group A ◽  
Covalently Linked

ABSTRACT The important human pathogen Streptococcus pyogenes (group A streptococcus GAS), requires several surface proteins to interact with its human host. Many of these are covalently linked by a sortase enzyme to the cell wall via a C-terminal LPXTG motif. This motif is followed by a hydrophobic region and charged C terminus, which are thought to retard the protein in the cell membrane to facilitate recognition by the membrane-localized sortase. Previously, we identified two sortase enzymes in GAS. SrtA is found in all GAS strains and anchors most proteins containing LPXTG, while SrtB is present only in some strains and anchors a subset of LPXTG-containing proteins. We now report the presence of a third sortase in most strains of GAS, SrtC. We show that SrtC mediates attachment of a protein with a QVPTGV motif preceding a hydrophobic region and charged tail. We also demonstrate that the QVPTGV sequence is a substrate for anchoring of this protein by SrtC. Furthermore, replacing this motif with LPSTGE, found in the SrtA-anchored M protein of GAS, leads to SrtA-dependent secretion of the protein but does not lead to its anchoring by SrtA. We conclude that srtC encodes a novel sortase that anchors a protein containing a QVPTGV motif to the surface of GAS.

scholarly journals Identification and Characterization of an Antigen I/II Family Protein Produced by Group A Streptococcus

2006 ◽  
Vol 74 (7) ◽  
pp. 4200-4213 ◽  
Author(s):  
Shizhen Zhang ◽  
Nicole M. Green ◽  
Izabela Sitkiewicz ◽  
Rance B. LeFebvre ◽  
James M. Musser
Keyword(s):  
Cell Surface ◽  
Group A Streptococcus ◽  
Bacterial Pathogen ◽  
Severe Infection ◽  
Genomic Islands ◽  
Oral Streptococci ◽  
Group B Streptococci ◽  
Gram Positive ◽  
Group A

ABSTRACT Group A Streptococcus (GAS) is a gram-positive human bacterial pathogen that causes infections ranging in severity from pharyngitis to life-threatening invasive disease, such as necrotizing fasciitis. Serotype M28 strains are consistently isolated from invasive infections, particularly puerperal sepsis, a severe infection that occurs during or after childbirth. We recently sequenced the genome of a serotype M28 GAS strain and discovered a novel 37.4-kb foreign genetic element designated region of difference 2 (RD2). RD2 is similar in gene content and organization to genomic islands found in group B streptococci (GBS), the major cause of neonatal infections. RD2 encodes seven proteins with conventional gram-positive secretion signal sequences, six of which have not been characterized. Herein, we report that one of these six proteins (M28_Spy1325; Spy1325) is a member of the antigen I/II family of cell surface-anchored molecules produced by oral streptococci. PCR and DNA sequence analysis found that Spy1325 is very well conserved in GAS strains of distinct M protein serotypes. As assessed by real-time TaqMan quantitative PCR, the Spy1325 gene was expressed in vitro, and Spy1325 protein was present in culture supernatants and on the GAS cell surface. Western immunoblotting and enzyme-linked immunosorbent assays indicated that Spy1325 was produced by GAS in infected mice and humans. Importantly, the immunization of mice with recombinant Spy1325 fragments conferred protection against GAS-mediated mortality. Similar to other antigen I/II proteins, recombinant Spy1325 bound purified human salivary agglutinin glycoprotein. Spy1325 may represent a shared virulence factor among GAS, GBS, and oral streptococci.

scholarly journals Molecular basis for recognition of the Group A Carbohydrate backbone by the PlyC streptococcal bacteriophage endolysin

2021 ◽  
Author(s):  
Harley King ◽  
Sowmya Ajay Castro ◽  
Amol Arunrao Pohane ◽  
Cynthia M. Scholte ◽  
Vincent A. Fischetti ◽  
...  
Keyword(s):  
Cell Wall ◽  
Active Sites ◽  
Group A Streptococcus ◽  
Attractive Alternative ◽  
Cell Wall Polysaccharides ◽  
Cell Wall Binding ◽  
Progeny Phage ◽  
Group A ◽  
A Cell ◽  
Species Specific

Endolysins are peptidoglycan (PG) hydrolases that function as part of the bacteriophage (phage) lytic system to release progeny phage at the end of a replication cycle. Notably, endolysins alone can produce lysis without phage infection, which offers an attractive alternative to traditional antibiotics. Endolysins from phage that infect Gram-positive bacterial hosts contain at least one enzymatically active domain (EAD) responsible for hydrolysis of PG bonds and a cell wall binding domain (CBD) that binds a cell wall epitope, such as a surface carbohydrate, providing some degree of specificity for the endolysin. Whilst the EADs typically cluster into conserved mechanistic classes with well-defined active sites, relatively little is known about the nature of the CBDs and only a few binding epitopes for CBDs have been elucidated. The major cell wall components of many streptococci are the polysaccharides that contain the polyrhamnose (pRha) backbone modified with species-specific and serotype-specific glycosyl side chains. In this report, using molecular genetics, microscopy, flow cytometry and lytic activity assays, we demonstrate the interaction of PlyCB, the CBD subunit of the streptococcal PlyC endolysin, with the pRha backbone of the cell wall polysaccharides, Group A Carbohydrate (GAC) and serotype c-specific carbohydrate (SCC) expressed by the Group A Streptococcus and Streptococcus mutans, respectively.

scholarly journals Studies on the cell wall of group A streptococcus, with special reference to the T antigen

1960 ◽  
Vol 15 (5) ◽  
pp. 470-473
Author(s):  
Makoto NAKAZAWA ◽  
Yuya NAKAMURA ◽  
Nobuyuki SAKAI
Keyword(s):  
Cell Wall ◽  
Special Reference ◽  
Group A Streptococcus ◽  
T Antigen ◽  
Group A
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